Building a simple game with Scratch

• Reset the program Choose "new" from the file menu. Do not save the file.
• Be sure the "motion" tiles are visible The blue motion tiles should be visible. Click on the motion button if necessary.
• Experiment with the tiles Double-click on the 'turn 15 degrees' tile. Watch what happens to the cat.
• Put the 'move 10 steps' tile in the script area the center area is where you build scripts
• Connect the 'turn 15 degrees tile When a white bar appears, the tiles will snap together
• Surround the tiles with the 'forever' loop Switch to the orange 'control' tiles. Drag the 'forever' loop to the center. Drag the connected tiles so they are in the 'alligator mouth' of the loop.
• Add the 'When flag clicked' tile This tile is shaped like a hat. It sits on top of the other elements
• Test your program Click on the green flag (upper right corner) Click the stop sign when you're done.
• Get rid of the blue blocks Now we're going to turn this animation into a game. Drag the blue tiles into the tile area to delete them.
• Add an 'if' block to the script You should still be showing the orange tiles. Find the 'if' block (not 'forever if' or 'if - else' - They're a bit different.) Place the if block inside the forever loop
• Add a condition The hexagon shape inside the if statement requires a new type of statement. Go to the light blue 'sensing' tiles.
• Find the keyboard sensor Locate the tile that says 'key <space> pressed?' Place this tile in the appropriate part of the if tile
• Test for the right arrow Use the small triangle on the key tile. Click to get a menu of keys, and choose 'right arrow' from this menu.
• Add 10 to x If the user clicks the right arrow, we want to move to the right. Go to the 'motion' tiles. X determines side-to-side motion. Place the 'change x by <10>' tile inside the if block.
• Test the program Use the green flag to see if the program works. The cat should move to the right when the right arrow is pressed.
• Copy the if block Move the mouse to the if statement and right-click. Choose 'duplicate' from the menu. A copy of the if block will appear. Drag this under the first if block (be sure the ifs are NOT nested.)
• Change the second if statement The second if statment tests for the left arrow
• Move the sprite by -10 Move the sprite to the left by changing x a negative amount
• Add vertical motion See if you can make the sprite also move up and down

Bonus challenges

Try these additional challenges if there's nobody waiting for a turn or at home on your own:

• Build a target sprite Add a new sprite. You can get one from the library or draw your own.
• Animate your sprite Each sprite can have multiple 'costumes' or images. You can make your sprite dance or whatever by flipping through the costumes
• Have a sprite move on its own Make the target sprite move all on its own.
• Wrap around the edges It's easy to make a sprite bounce. Can you make it wrap?
• Add a timer and scorekeeping Give your game points and a time limit